The situation when the refrigerator suddenly stops freezing, and the compressor is silent, takes every owner by surprise. Often the cause of a breakdown is the failure of the start-up relay, which controls engine starting. In such cases, a master or experienced amateur needs to start the compressor directly to check the serviceability of the motor itself, bypassing the control circuit.
This procedure requires extreme caution, since you are dealing with a high voltage of 220 volts. Incorrect connection may result in short circuit, electric shock, or permanent burnout of the motor windings. Before starting any work, it is necessary to completely de-energize the household appliance by unplugging the cord from the socket.
In this article we will analyze in detail the structure of the electrical circuit, diagnostic methods and a step-by-step algorithm for direct start-up. You will learn how to safely test functionality unitusing a minimal set of tools. This knowledge will help save time on troubleshooting and avoid purchasing expensive but unnecessary equipment.
Design and principle of operation of the starting relay
To understand the starting process, you need to know what function the relay performs in normal operation of the refrigerator. The starting protection device is responsible for supplying voltage to the starting winding of the engine only at the moment of start. As soon as the rotor reaches the required speed, the current in the circuit drops, and the relay turns off the starting winding, leaving the working winding.
There are two main types of such devices: induction (with a coil) and posistronic. Posistor is a ceramic element that, when heated by current, changes its resistance, opening the circuit. Induction models rely on the magnetic field created by the current in the coil to move the core.
If the relay is faulty, the contacts may stick or, conversely, not close, which leads to a humming motor without starting or complete silence of the unit. That is why checking the motor directly is the first diagnostic step. It allows you to eliminate damage to the engine itself and focus on the control system.
It is important to note that in modern models of refrigerators Indesit, Atlant or LG relays of different designs can be used. However, the principle of separation of windings (starting and working) remains the same for all asynchronous motors for household use.
Necessary tools and safety measures
Before you start work, you need to prepare the workplace and tools. You will need a screwdriver to remove the compressor housing, pliers to manipulate the wires, and a multimeter to check the integrity of the windings. It would also be a good idea to have electrical tape on hand and, possibly, a button for forced start.
Safety is priority number one. Working with 220V electricity poses a real threat to life. All manipulations with connecting wires should be carried out only with the power cord unplugged from the network. You can only plug the device into the outlet for a short time to check, keeping your hands away from live parts.
⚠️ Attention: Never touch the metal parts of the compressor housing or bare wires while applying voltage. The risk of receiving an electric shock at this moment is maximum.
For ease of testing, you can assemble a temporary circuit with a button. This will allow you to control the moment the pulse is applied to the starting winding. Using such a circuit reduces the risk of motor overheating, since the starting winding is not intended for long-term operation.
- 🔧 A screwdriver with a flat and Phillips blade for dismantling the protective box.
- 🔌 Wires with alligator clips for temporary connection of contacts.
- 📏 Multimeter for measuring winding resistance and checking for breakdown.
- 🧤 Dielectric gloves for additional hand protection.
Diagnostics of windings before starting
Before applying voltage, it is critical to check the condition of the motor windings. There are three of them inside the compressor: working, starting and general. Incorrect identification of the terminals can lead to a short circuit or starting the engine in the opposite direction, which is dangerous for mechanics.
Using a multimeter in resistance measurement mode, test all three contacts among themselves. The smallest resistance will show the working winding, the average will show the starting winding, and the sum of these two values will give the resistance between the extreme contacts (common). This data will help you connect the circuit correctly.
⚠️ Attention: If the multimeter shows a resistance close to zero or, conversely, infinity between the housing and any of the contacts, the compressor is faulty. It is strictly prohibited to start such a motor.
You should also carefully inspect the compressor itself for physical damage. If traces of oil, rust or melted insulation are visible, this may indicate an interturn short circuit or a breakdown to the housing. In such cases, direct launch will not produce results.
For different models of refrigerators, be it Beko or Stinol, the location of the contacts may differ, but the logic of their operation is the same. Always check the diagram printed on the relay body, if it is readable, or use reference data for a specific series of motors.
Step-by-step connection diagram directly
The process of starting a compressor without a relay is to simulate the operation of the starting device. You need to apply voltage to the working winding constantly, and to the starting winding - briefly, only at the moment of start. For this, a circuit with two wires and a button is used.
First, determine the common wire (Common). Connect one of the power wires to it (for example, zero). Then find the working winding (it has less resistance relative to the common wire) and connect the second power wire (phase) to it. Now the motor is ready to work, but will not start on its own.
To start the rotor, you need to briefly apply a phase to the starting winding. To do this, use a button or simply touch the wire to the contact of the starting winding for a split second. If the compressor is working properly, you will hear a characteristic hum and feel vibration.
Connection diagram:1. Phase (L) -> Working winding (constant)
2. Zero (N) -> Common wire (permanent)
3. Phase (L) -> Starting winding (briefly through the button)
☑️ Check before starting
After a successful start, the compressor will work until you turn off the power. It is important to monitor the temperature of the housing: if it starts to heat up excessively in a short time, it means that there are hidden defects in the motor or the thermal regime is disturbed.
Typical errors and troubleshooting
One of the most common mistakes is confusion between the starting and operating windings. If they are mixed up during direct start, the engine may hum, but not rotate, or rotate in the opposite direction, which will lead to damage to the valve group. Always double-check the resistance measurements.
Holding the start button for a long time is another common mistake. The starting winding is not designed for long-term operation under load. If you hold the button down for more than 2-3 seconds, the wire insulation may melt, which will lead to an interturn short circuit.
Sometimes users forget about the capacitor, if it is provided for in the design. In some circuits, the start relay includes a phase-shifting capacitor. The absence of a capacitor during direct starting can make starting impossible for powerful motors.
| Problem | Possible cause | Solution |
|---|---|---|
| Buzzes, but does not start | Stuck or not start | Check the mechanics, try to start with a push |
| Knocks out the machines | Short circuit | Check the windings for breakdown, replace the compressor |
| Strong is heating up | Winding malfunction | Measure the current, check the resistance |
Why does the housing heat up during operation?
During operation, the compressor heats up to 70-90 degrees. This is fine. However, if the temperature exceeds 100 degrees or the heating occurs unevenly, this indicates a refrigerant circulation problem or electrical malfunction.
Analysis of results and further actions
If you managed to start the compressor directly and it runs smoothly, without extraneous knocks or vibrations, then the engine itself is working. The problem lies in the control system: relay, thermostat or wiring. In this case, replacing the starter protection device will solve the problem.
If the motor hums, jerks or blows fuses, more in-depth diagnostics or replacement of the unit will be required. Sometimes the “wedging” method helps, but it requires special equipment and skills, so it is not recommended at home.
After checking, be sure to restore the standard connection diagram. Operating a refrigerator without a relay is only permissible for diagnostic purposes for a short time. Continuous operation without thermal protection will result in overheating and fire.
Do-it-yourself refrigerator repair is possible, but requires adherence to technology. If you are not confident in your abilities, it is better to entrust the work to a professional, since mistakes can cost more than calling a specialist.
Frequently asked questions (FAQ)
Is it possible to leave the refrigerator running without a relay all the time?
It is absolutely not possible. The relay performs a protection function. Without it, if overloaded or jammed, the motor will burn out in a matter of minutes, which can lead to a fire.
What capacitor is needed to start the compressor?
The parameters of the capacitor depend on the engine power. Typically, starting capacitors with a capacity of 20 to 50 μF are used for a voltage of at least 300V. The exact data is indicated on the motor nameplate.
Why does the compressor start only with a push?
This is a sign of bearing wear or insufficient torque due to low voltage in the network. It is also possible that the contacts of the starting relay may burn out.
Is it dangerous to touch copper tubes while the compressor is running?
When starting directly without standard protection, the risk of insulation breakdown on the housing increases. Touching the metal parts of a running unit is dangerous to life.
How to determine that the winding has burned out?
If the multimeter shows infinite resistance (open) or resistance close to zero (short circuit) between the terminals, the winding is faulty. A burning smell may also be a sign.